Apparatus for finishing and reconditioning edged tools



Jan. 14, 1941. J. E. BURNS 2,228,385

APPARATUS FOR FINISHING AND RECONDITIONING EDGED TOOLS Filed Jan. '27, 1959 s Sheets-Sheet 1 Jan. 14, 1941. J BURNS 2,228,385

APPARATUS FOR FINISHING AND RECONDITIONING EDGED TOOLS Filed Jan. 27, 1939 SSheets-Sheet 2 Jan. 14, 1941. J. E. BURNS 2,228,385

APPARATUS FOR FINISHIN G AND RECONDITIONING EDGED TOOLS A a T w 9 7 Filed Jan. 2'7, 1939 3 Sheets-Sheet 3 H. M g M1 U Hi M) m M 1 Patented Jan. 14, 1941 APPARATUS FOR FINISHING AND RECON- DITIONING EDGED TOOLS Joseph E. Burns, Syracuse, N. Y. Application January 27, 1939, Serial No. 253,189

7 Claim.

This invention appertains to an improved apparatus for finishing and reconditioning edged tools, and more especially, to machines for grinding or sharpening knives, and the like.

The invention has for its primary object the provision of a simple and efiicient power operated grinder, which is of such compactness and small size as to be readily portable.

A further object of my invention is to provide an improved grinding machine which embodies a pair of rotary grinding elements, each composed of axially spaced discs, with the discs of one grinding element arranged in overlapped relation with the discs of the other grinding element, and the grinding elements being preferably rotated in the same direction.

Another object of the invention is to provide an improved mounting for the rotary grinding elements above referred to, wherein the grinding elements are adjustable relative to each other to permit the grinding of different bevels, while at the same time affording a rigid support for the grinding elements to assure accuracy and precision of the grinding action performed thereby.

Still another object of the invention is to provide an improved housing or casing for the rotary grinding elements, the housing or casing being so constructed as to substantially completely enclose the grinding elements and thereby serve to collect the abrasive dust and such metal particles as may be ground off of the knife or edged tool during the grinding operation, thus preventing these fine particles from being disbursed into the air. Consequently, the grinder construction is such as to promote safety from a health standpoint, and at the same time minimize injury to the operator, or others working in the vicinity of the grinder, by virtue of the enclosing of the grinding elements.

The invention further contemplates an improved form of housing or casing for the grinding element, wherein provision is made for rendering the grinding elements readily and conveniently accessible for replacement and/or reconditioning, and as to the latter, provision is made for aiding in the support and guiding of a dressing tool or stone used in the reconditioning or dressing of the grinding faces of the grinding elements.

Other and further objects and advantages of the invention will be hereinafter described, and the novel features thereof defined in the appended claims.

In the drawings:

Figure 1 is a perspective view of an apparatus embodying my invention and primarily intended for use in sharpening or reconditioning knives and other edged tools, the apparatus being viewed from the rear;

Figure 2 is a view of the apparatus in front of the casing removed and illustrating the mannet in which the grinding elements are adjusted to cause the desired bevel to be ground upon the knife or other edged tool, as the case may be; t Figure 5 is a horizontal sectional view, taken approximately on the line 55 of Figure 2;

Figure 6 is a view of the front wall of the casing, in elevation, as viewed from the rear thereof;

Figure 7 is an enlarged fragmentary detail view showing the position of adjustment of the rotary grinding elements to produce a short or steep bevel on the edge of the knife; and

Figure 8 is a view corresponding to Figure 7, illustrating the rotary grinding elements in another position of adjustment to produce a long bevel of less abruptness on the edge of the knife.

Like reference characters designate corresponding parts in the several figures of the drawings, wherein I designates a base of substantially rectangular form and of suitable thickness to insure rigidity. The base may be made of any suitablematerial, but is preferably made of metal such as cast iron or the like. At the front edge of the base there is provided a wall 2, which extends upwardly therefrom and which is preferably an integral part of the base, the wall also being of sufficient thickness to insure rigidity.

Extending through the upper end of the wall 2 is a bolt or stud 3, having a clamping nut 4 threadedly received thereon at the front side of the wall 2. Pivotally mounted upon the rear end of the bolt or stud 3 is a pair of arms 5, 5, which are pivotally adjustable relative to each other and are adapted to be rigidly secured in any selected position of adjustment by means of the clamping nut 4. The upper extremity of each of the arms 5 is preferably provided with a laterally offset extension 5, and each arm is provided with apair of axially spaced aligned bearings 6, in which an arbor l is journaled.

Mounted upon the forward extremity of each of the arbors 1, I so as to be rotatable with the arbors is a grinding element, generally designated 8. The grinding elements 8, 8 may have any suitable construction, but I prefer to employ a plurality of axially spaced, relatively thin discs 9 composed of abrasive material known in the trade as a Whetstone mixture. Of course, the abrasive composition may be varied to meet different requirements, but I have found that for general purposes and for sharpening knives and edge.

aging the same.

As clearly shown in the drawings, the discs 9, which constitute each of the grinding elements 8. are so arranged that the discs of the respective I elements 8, 8 overlap upon" each other. The extent of the overlap can be varied by adjusting the arbors 1, 1 relativeto each other, as permitted by the pivotal adjustment of the supporting arms 5, 5 about the bolt or stud 3, and this variation of the overlapping of the discs may be availed of to vary the angle or bevel to be ground on the knife or other edged tool, as will be hereinafter more fully explained.

Mounted upon the base I and secured thereto in any suitable manner, as by screws I0, is an electric motor II having a pulley I2 ailixed to its driving shaft. The pulley I2 is provided with a pair of grooves, each of which is adapted to receive a belt I3 for driving the respective arbors 1, 1. Fixed to each arbor 1 intermediate its axially spaced bearings 6 is a pully I4, about which the respective belts l3, l3 pass to transmit power from the motor II to the arbors. The driving shaft l5 of the motor is preferably coaxial with the stud or bolt 3 so that the adjustment of the arbors 1, 1 relative to each other, as previously described, can be attained without necessitating a variation in the length of the belts I3, I3, the latter being preferably rubber belts having substantially circular or V-shaped crosssection. A switch I6 is preferably provided for convenience to permit starting and stopping of the motor at will.

As clearly shown in Figures 1 and 2, the belts I3, I3 are straight belts, so that the arbors I, 1 and the grinding elements 8, 8 carried thereby will consequently be rotated in the same direction when the motor II is set into operation. I have found that this gives the best results inasmuch as a steadier engagement of the knife or other implement with' the grinding elements may be maintained during the grinding or sharpening operation. I have found that such uniformity of grinding cannot be attained to any practical degree where the grinding elements are rotated in opposite directions with the knife engaging portions of the grinding elements moving towards each other. In such an arrangement, the grinding elements tend to pinch or grab the edge of the knife being sharpened, resulting in the production of a very irregular sharpened edge. Moreover, unless considerable care is used, and even with the exercise of great care, irreparable injury to the knife and/or the grinding elements will frequently result.

Rotation of the grinding elements in opposite directions so that the tool engaging, portions thereof move outwardly or away from each other is also open to serious objections. In such an arrangement, the knife has a tendency to vibrate or bounce during the grinding operation, and this produces a very ragged and uneven sharpened All of these difiiculties are overcome by rotating the grinding elements in the same direction as contemplated by the present invention.

Secured to the rear face of the wall 2, as by means of fastening screws I1, and extending upwardly from the base I, is a plate I8. The plate is apertured to permit the stud or bolt 3 to freely pass therethrough. In other words, the stud or bolt 3 connects the arms 5, 5 to the wall 2, rather than to the plate I8, so that the latter may be substanially ligher and less rigid than the wall 2. The upper end of the plate I8 constitutes the rear wall of a casing or housing, generally designated I9, and is provided with a pair of elongated openings affording adequate clearance for the arbors 1, 1, which extend through the same and which are movable relative to each other in effecting the adjustments hereinbefore referred to. Extending downwardly from the upper edge of the plate I8, and disposed substantially midway between the openings 20, 20 and the opposite sides of the plate, is a slot 2|, in which the knife or other edged tool to be sharpened is adapted to be inserted, as clearly shown in Figure l. The slot 2| preferably terminates at its lower end substantially in the plane of the axes of the arbors 1, I when the arbors and disposed at about their maximum limit or adjustment away from each other.

Forwardly spaced from the plate I8 and secured thereto, is a front plate 22 forming the front wall of the casing I8. It is to be understood that the plates l8 and 22 are spaced from each other a sufficient distance to afford clearance with respect to the front and rear faces of the grinding elements 8, 8. .The front plate 22 extends only a short distance below the bottoms of the grinding elements 8, 8, with its lowermost curved edge terminating somewhat above the upper extremity of the upright wall 2. Formed integrally with the front plate 22 and extending rearwardly therefrom into abutting engagement with the front face of the plate I8 is a flange 23. As clearly seen in the drawings, the flange 23 is formed only on about the lower half of the plate 22, and terminates at its upper extremities in laterally offset, substantially horizontal ledges 24 disposed at opposite sides of the casing IS. The purpose of these ledges 24, 24 will hereinafter become more fully apparent. The plate 22 is also provided with a substantially vertical slot 25 extending downwardly from its upper edge, corresponding to and in register with the slot 2I in the plate I8. A pair of elongated openings 26, located respectively at opposite sides of the slot 25, are also provided in the front plate 22 in register with the corresponding openings 28, 20 in the plate I8, so as not to interfere with the adjustment of the relative spacing of the arbors 1, 1.

Pivotally mounted between the spaced plates I8 and 22, at opposite sides of the slots 2|, 25, is a pair of cover members or closures 21, 21, each extending from a point adjacent to the slots 2I, 25, across the upper edges of the plates I8, 22, and down to the ledges 24, 24. The width of each closure 21 (from front to back) is preferably such that the closure overlaps the edges of both plates I8 and 22 so that when the closures 21, 21 are closed, as shown in full lines in Figures 1 and 2, they will tightly abut against the edges of the plates I 8, 22, and also against the ledges 24 at their lower free extremities, thus effectively closing the casing I9 against the escape of dust and fine abrasive or metal particles. Any convenient means for pivotally mounting the closures 21, 21 may be availed of, but for the purposes of illustration, I have shown screws 28 extending through the front and rear plates 22 and I8, respectively, into the hinged ends of the closures 21, 21. The hinged ends of the closures 21 are preferably availed of as spacers to positively space apart the upper ends of the plates I8, 22. 29 designates a lug or boss preferably mounted on the front face 2,228,385 of the plate 18 so as to constitute a spacer coacting with the lower end of the plate 22. A screw 28', having threaded engagement with the spacer 29 and extending through the plate 22 into the latter, contributes to the action of the crews 28 in assembling together the parts of the cleaning out the accumulations collected within the casing.

In the use of my invention to sharpen or recondition a knife or other edged tool, the grinding elements 8, 8 are first adjusted to correspond with the particular bevel or angle to be ground on the edge of the tool. In making this adjustment, the clamping nut 4 is firstloosened with the aid of a wrench or other convenient tool, as shown in Figure 4, thereby freeing the supporting arms 5, 5 for pivotal movement to enable the arbors l, l to be moved towards or away from each other, as desired. The angle of intersection of the overlapped peripheries of the grinding elements 8, 8 (indicated by the reference Xin the drawings) determines the angle or bevel which will be ground on the edge of the knife during the sharpening operation. Obviously, if the arbors l, 1 are moved closer together, this angle will be increased due to the intersection of the peripheries of the grinding elements 8, 8 at a point farther above the axes of rotation of the grinding elements, thereby causing the grinding elements to produce a relatively short or abrupt angle or bevel on the edge of the knife, as clearly shown in Figure 7. Conversely, if the arbors l, I are spaced farther apart, the angle X will decrease due to the intersection of the peripheries of the grinding elements 8, 8 at a point relatively closer to the axes of rotation. In the latter case, as represented in Figure 8, the angle or bevel produced on the edge of the knife as a result of the grinding operation will be relatively long and less abrupt.

In effecting the adjustment of the grinding elements 8, 8, as described above, care should be taken to the end that the intersection of the peripheries of the overlapping discs 9 of the multiple disc grinding wheels is maintained in register with the slots 2| and 25. By inserting the knife or other implement which is to be sharpened into the slots 2|, 25, as shown in Figure 1, during the adjusting operation, and centering the grinding elements 8, 8 so that they both engage the edge of the implement while so positioned in the knife slots, the correct adjustment can be facilitated. If preferred, the front of the casing l9 may be removed prior to adjusting the position of the grinding elements 8, 8, and then carrying out the adjusting operations as described above and in the manner particularly shown in Figure 4. However, it is not essential that the front of the casing be removed for this purpose.

After effecting the desired adjustment of th grinding elements 8, 8 so as to produce the required bevel or angle on the edge of the knife or other edged implement, the motor II is then set into operation, as by manipulating the switch Hi. When the grinding elements 8,, 8 have reached their normal speed of operation, the knife or other implement is then inserted in the registered slots 2|, 25, which together form a guide for guiding the implement into operative engagement with the peripheral grinding faces of both of the grinding elements 8, 8 simultaneously. By drawing the knife or other implement, as the case may be, backwardly and forwardly while held in the position as illustrated in Figure l, and

at the same time exerting a slight downward "pressure upon the same, the edge will be sharp- \ened uniformly throughout the length thereof. Needless to say, no particular-skill is required to perform the sharpening operation, and equally good resultscan be attained with perfect safety in performing both initial sharpening operations as well as resharpening or reconditioning operations, even where the operator has had no previous experience insuch operations.

Should the peripheral grinding faces of the discs 9 which form the respective grinding elements 8, 8 become uneven through long use, or become glazed or otherwise ineffective for efficient use, the grinding elements may be dressed or trued up by employing an abrasive dressing stone orother suitable tool in the manner illustrated in Figure 2. In this figure, 30 designates the dressing stone, which may be a block of Carborundum, preferably at least as wide as the combined transverse width of each of the grinding elements 8, but not greater than the space between the plates l8 and 22, so that by raising the closure member 2'! and resting the stone 38 upon the ledge 24, with the inner end of the stone in engagemcnt with the peripheral grinding face of the grinding element 8, the grinding faces of each of the latter may be effectively reconditioned without removal of the grinding elements from the machine. During this operation, the ledges 28 may be availed of to support the dressing stone or tool 38 in proper alignment with the peripheral faces of the respective grinding elements 8, 8, while at the same time, the closures 21 prevent the particles of abrasive from being thrown out of the casing and causing possible injury to the operator.

Wherever the term grinding or abrasive element has been used herein, and having particular reference to the rotary elements 8, 8, it is to be understood that the same should be broadly construed as embracing buffing or other types of finishing elements. Obviously, rotary bufiing wheels may be substituted for the abrasive grinding elements 8, 8. Likewise, sanding wheels, particularly those made of abrasive cloth, may be utilized according to the type of operation which is desired to be performed in the use of the apparatus. For example, the apparatus is eminently suited for performing a number of different operations in the manufacture of cutlery and other edged implements, wherein the implement must be first subjected to a preliminary grinding or sharpening operation, followed by a finishing of the sharpened edge through means of finishing stones or other finer abrasive instrumentalities, and then followed by a final bufling operation. Still other uses will readily sugge' t themselves when the construction and operation of my invention is fully understood.

In the preferred embodiment of the invention,the grinding wheel 8, which has the outermost or forward disc 9 in the overlapped arrangement of the discs of the respective wheels 8, 8, is preferably driven in such direction that the periphery of this wheel and the outermost disc moves upwardly against the edge of the knife. According to the arrangement illustrated in'the drawings, the outermost disc 9 is the front disc of the righthand grinding wheel 8 in Figures 2, 4 and 5, and the direction of rotation of the wheels 8, 8 is shown by the arrows in Figure 4. This produces a smoother or cleaner edge on the knife or other instrument being sharpened instead of a wire or feather edge.

While the specific details have been herein shown and described, the invention is not confined thereto, as changes and alterations may be made without departing from the spirit thereof as defined by the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is-- 1. Apparatus of the class described, comprising a support, a pair of rotary elements mounted thereon with their axes in radially spaced relation, and a casing for enclosing said rotary elements, said casing including spaced walls respectively disposed at opposite sides of the rotary elements, one of said walls having a flange projecting therefrom into abutting engagement with the other wall and extending partially around the rotary elements, means for detachably securing one wall to the other, and movable closures carried by said walls and normally extending about the remainder of the distance around each of the rotary elements, across the space between the walls aforesaid, to a point about midway between the axes of the respective rotary elements so as to leave a space therebetween to permit engagement of a work-piece with the rotary elements.

2. Apparatus of the class described, comprising a support, a pair of rotary elements mounted thereon, and a casing for enclosing said rotary elements, said casing including spaced walls respectively disposed at opposite sides of the rotary elements, one of said walls having a flange projecting therefrom into abutting engagement with the other wall and extending partially around the rotary elements, said flange terminating at its opposite ends in outwardly directed ledges disposed adjacent to the peripheries of the respective elements, and a movable closure carried by said walls and normally extending about the remainder of the distance around each of the rotary elements, across the space between the walls aforesaid.

3. Apparatus as claimed in claim 1, wherein the rotary elements are each composed of a plurality of axially spaced discs, with the discs of one of the rotary elements overlapping the discs of the other rotary element, and the casing is provided with a slot extending inwardly from its edge in alignment with and at least to the line of intersection of the peripheries of the rotary elements, said slot being relatively narrow and not substantially greater than the thickness of a knife or other edged implement.

4. Apparatus as claimed in claim 1, wherein the casing is provided with a slot extending inwardly from its edge midway between the axes of rotation of the rotary elements, and terminating at its inner end adjacent to the peripheries of both rotary elements.

5. Apparatus as claimed in claim 1, wherein the casing is provided with a slot extending inwardly from its edge midway between the axes of rotation of the rotary elements, and terminating at its inner end adjacent to the peripheries of both rotary elements, and wherein there is a movable closure pivotally connected to the spaced walls of the casing at opposite sides of the slot aforesaid for swinging movement towards and away from the edge of the casing.

6. Apparatus of the class described, comprising a rigid support, a pair of arms normally rigidly connected to said support, but adjustable relative to each other, an arbor journaled in each of said arms and carrying a rotary element, driving means mounted on said support at one side of said arms and operatively connected to said arbors for rotating the latter, and a casing including substantially parallel walls axially spaced from each other at opposite sides of the rotary elements and. attached to said support for substantially enclosing said rotary elements, said casing having registered slots in said opposite walls thereof extending inwardly from one edge of the casing to a point permitting engagement of a knife or other edged implement with the peripheral faces of both rotary elements, simultaneously, when disposed in said slots, and said casing also including a laterally offset ledge disposed adjacent to the periphery of each rotary element and constituting a support or rest for a dressing or reconditioning instrumentality for dressing or truing the peripheral faces of the respective rotary elements.

7. Apparatus of the class described, comprising a base, a rigid support extending upwardly from said base, a pair of arms pivotally connected to said support and adjustable relative to each other in a vertical plane, an arbor journaled in the free extremity of each arm and carrying a rotary element, motor means mounted on said base and having a driving shaft axially spaced from but coaxial with and terminating relatively close to the pivotal connection of the arms aforesaid with their support, means operatively connecting the driving shaft-of the motor means with the arbors aforesaid for driving the latter, a plate secured at its lower end to the support and terminating above the uppermost edges of the rotary elements, said plate being disposed intermediate the arms and one side of the rotary elements, and having elongated openings therein through which the respective arbors freely extend, and a second plate spaced from the first plate and disposed at the opposite side of the rotary elements and removably attached to the first plate, said second plate terminating at its lower end somewhat below the lowermost edges of the rotary elements and having a flange extending therefrom across the space between the plates below the axis of rotation of the rotary elements and into abutting engagement with the first plate, each of said plates aforesaid having a slot registering with a slot in the other plate and extending downwardly from the upper edges thereof for a substantial distance midway between the axes of rotation of the rotary elements, and a pair of closure members pivotally attached to the spaced plates adjacent to the upper ends of the registered slots aforesaid at opposite sides thereof, and extending across the space between said plates around the edges of the latter above the axes of rotation of the rotary elements, the free ends of said closure members having abutting engagement with the upper opposite ends of the flange on the second mentioned plate.

JOSEPH E. BURNS. 

